Signaling system



NW. 2%, i935. "r. L. DIMOND 2,

' SIGNALING SYSTEM FiledFeb. 16, 1935 FIG. I

A TTORNE Y Patented Nov. 26, 1935 UNITED STATES SIGNALING SYSTEM ThomasL. Dimond, Rutherford, N. J assignor to Bell Telephone Laboratories,Incorporated, New York, N. Y., a corporation of New York ApplicationFebruary 16, 1935, Serial No. 6,784

9 Claims.

This invention relates to signaling systems and particularly to systemsin which automatic switches are directively controlled by currentimpulses in a direct current signaling circuit.

The object of the invention is to provide an improved impulse circuitarrangement which is capable of responding to impulses incoming overlines of high resistance and over lines having a low insulationresistance.

In an impulse receiving device arranged in accordance with thisinvention, one three-element gas-filled tube is energized in response tothe closing of a direct current signaling circuit to operate an impulsereceiving relay and another threeelement gas-filled tube is energized inresponse to the opening of the signaling circuit to operate a secondimpulse receiving relay, the operating circuits for each one of theimpulse receiving relays being controlled by the other of these relays.The impulse receiving relays may be effective to control an impulseregister or to control a circuit by directively operating an automaticswitch.

A feature of the invention is an impulse receiving device comprising atransformer, two threeelement gas-filled tubes, a relayoperativelycontrolled by one of the tubes for responding to the closingof an incoming impulse circuit which includes a winding of thetransformer, and a relay operatively controlled by the other of thetubes for responding to the opening of the impulse circuit. The controlelement of one of'the tubes is connected to one secondary winding of thetransformer and the control element of the other tube is connected toanother secondary winding of the transformer. The anode of one of thetubes is connected to the winding of the relay which responds to theclosing of the incoming impulse circuit and the anode of the other tubeis connected to the winding of the relay which responds to the openingof the incoming impulse circuit; the operating circuit for each one ofthe relays is controlled by the other.

A more complete understanding of the invention may be obtained byconsidering the specific embodiments of the invention shown in thedrawing which forms a part of this specification. The

invention is not, however, limited in its application to these specificarrangements and is, in general, applicable to any signaling system inwhich selective signals are created by the opening and closing'of asignaling circuit.

Referring toeach of the three figures of the drawing, A represents asubscribers station in an automatic telephone system and IR representsimpulse receiving means.

The apparatus at station Aincludes a dial H], or an equivalent impulsesender, and is connected by line H to a central ofiice or exchange inwhich automatic switching equipment is provided for establishing aconnection between the line H and an idle impulse receiving means IR inresponse to the removal of the receiver at station A to originate acall. The impulse receiv-- ing means IR may be used to directly controlin succession each of a train of selective switches 10 to complete adesired connection or may be used to operate a register which thereaftercontrols the various switches through which a desired connection isestablished. Reference may be had to chapter III of the second editionof Automatic Telephony by Smith and Campbell for a description of anautomatic telephone system comprising switches of the well-knownStrowger type controlled by the dial impulses when dialed. Reference maybe had to: Patent No. 1,395,977 granted to F. A. Stearn et al. onNovember 1, 1921 for a description of a system comprising switches ofthe power-driven type which are revertively controlled by aregister-controller, set in accordance with trains of impulses createdby the operation of the dial at any calling subscribers station to whichthe register-controller is connected. The impulse receiving means IR, inFig. 1 comprises the transformer it, the two three-element hot-cathodegas-filled tubes i5 and I5 and the two relays H and 58. The transformerhas three windings, the primary winding being connected in series withthe central office battery and the line i i The inner ends of thesecondary windings of the transformer are connected to the 85 negativepole of the central ofiice battery; the outer end of the upper windingis connected to the grid or control element of the tube l5; and theouter end of the lower winding is connected to the grid or controlelement of tube it. The cathode of. each tube is connected to thenegative pole of central ofiice battery so that there is normally aninsufficient difference in potential between the grid and cathode tocause ionization of the gas. If necessary, batteries is and it may beconnected in series with the secondary windings of the transformer tonormally maintain the grid elements at a proper potential level. Theanode of tube 55 is connected in series with the winding of relay H andthrough the back contact of relay 58 to ground, the positive pole of thecentral office battery also being connectedto ground. The anode of tubeIt is connected in series with the winding of relay It to the lowerarmature of relay l1.

Each of tubes [5 and. I6 are filled to a low pressure with a gas such asneon, argon or helium; and the electrodes of each tube are so designedthat the gas becomes ionized upon impression of the required potentialacross the cathode and grid, whereupon the tube becomes a conductorbetween the cathode and anode. Although the potential normally impressedacross the cathode and anode is insufilcient to cause the breakdown ofthe tube, the tube remains energized even though the grid element isrestored to its normal negative potential, until the cathode to anodecircuit is opened or short-circuited.

Upon extension of line I l to the impulse receiving means IR, a circuitis closed from battery, through the primary winding of transformer l2over the lower conductor of line H, through the telephone instrument anddial H! at station A, back over the upper conductor of line H to ground.The closing of this circuit induces an electromative force in the upperand lower secondary windings of transformer l2, thereby temporarilyrendering the grid element of tube l5 less negative and the grid elementof tube I 6 more negative. The tube It does not respond; but thetemporary change in the potential of the grid of tube I5 causes theionization of the gas and the tube becomes a conductor, so that relay i1is operated by the current in the cathodeanode circuit. In operating,relay ll closes at its upper contacts a circuit which controls animpulse register or a selector switch. Relay I! also connects groundthrough its lower contacts to the winding of relay l8, but relay 58cannot immediately operate since the tube 13 is not energized.

When the subscriber at station A operates the dial I Q, the line I I isinterrupted by the dial contacts in usual manner. At the first openingof the line H, an electromotive force is induced in the secondarywindings of transformer I2, thereby temporarily rendering the grid oftube l5 more negative and the grid of tube 15 less negative. Thetemporary change in the potential of the grid of tube It causes theionization of the gas and the tube becomes a conductor, so that relay [8is operated by the current in the cathodeanode circuit of tube IS. Thechange in the potential in the grid of tube It does not cause itsdeenergization; but, when relay l6 operates, tube [5 is deenergized andrelay l1 releases, thereby opening the outgoing impulse circuit inresponse to the opening of the line H at dial Ill. The release of relayl1 causes the deenergization of tube 15 and the release of relay l8. Assoon as the line i l is again closed at dial ID, the electromotive forceinduced in the secondary winding of transformer It causes thereenergization of tube l5 and reoperation of relay l1, thereby againclosing the outgoing impulse circuit at the pper contacts of relay i7,Thus, each opening and closing of the line i l at the contacts of dialIt! causes a corresponding opening and closing of the outgoing impulsecircuit at the impulse receiving means IR.

The impulse receiving means IR shown in Fig. 2 is the same as that shownin Fig. 1, except that relay 2'! which is substituted for relay I! ofFig. 1 has an additional set of contacts to provide a locking circuitfor this relay. When relay 21 operates, the anode of the tube isshort-circuited so that the tube is immediately deenergized.

36, and the relays 3! and 38. The primary winding of the transformer isconnected in series with the central ofiice battery and subscribersline. One end of each of the secondary windings is connected to ground,the other ends being con- 5 nected to the grid elements of tubes 35 and36. The anode element of tube 35 is connected through the winding ofrelay 3! to the positive pole of battery 34, and the anode element oftube 36 is connected through the winding of relay 38 10 to the positivepole of battery 34, the negative pole of battery being connected toground. The cathode of tube 35 is normally connected through the backcontact of relay 38 to the negative pole of battery 33, the positivepole of bat- 15 tery 33 being connected to ground. The cathode of tube35 is connected to the lower front contact of relay 31. When the line isclosed and connected to the primary winding of transformer 32, theelectromotive force .induced in the secondary windings causes thebreakdown of tube 35 and the operation of relay 31. Relay 3'! closes atits upper contacts the outgoing impulse circuit and at its lowercontacts connects the cathode of tube 36 to the negative pole of battery33. When 55 the subscribers line is opened by the dial, theeleotromotive force induced in the secondary windings of transformer 32causes the breakdown of tube 35 and operation of relay 38. The operationof relay 38 causes the release of relay 3'! 80 thereby opening theoutgoing impulse circuit. The release of relay 3? causes the release ofrelay 38. When the line is again closed, at the end of the dial impulse,the tube 35 and relay 3'! are reenergized, thereby again closing theoutgoing impulse circuit.

What is claimed is:

1. In combination, a first circuit, a second circuit, a firstthree-element gas-filled tube, a second three-element gas-filled tube, afirst relay, 40 means including said first tube for operating said firstrelay in response to the closing of said first circuit, a second relay,means including said second tube for operating said second relay inresponse to the opening of said first circuit, and 45 means includingsaid tubes and relays for closing said second circuit in response to theclosing of said first circuit and for opening said second circuit inresponse to the opening of said first circuit.

2. In combination, a transformer, an impulse circuit including theprimary winding of said transformer, two three-element gas-filled tubes,the control element of one of said tubes being connected to onesecondary winding of said trans- 55 former, and the control element ofthe other of said tubes being connected to another secondary winding ofsaid transformer, a relay for operation in response to the closing ofsaid impulse circuit, another relay for operation in response 60 to theopening of said impulse relay circuit, the operating circuit for eachone of said relays being controlled by the other of said relays, andanother circuit controlled by one of said relays.

3. In combination, a circuit, means for opening 05 and closing saidcircuit, two three-element gasfilled tubes, two relays, the winding ofone of said relays being connected to an element of one of the tubes andthe winding of the other of said relays being connected to an element ofthe 70 other of said tubes, and circuit means for operativelyassociating said signaling circuit with the control element of each ofsaid tubes, the closing of said circuit being effective to cause thebreakdown of one of the tubes and operation of one 75 of the relays, andthe opening of said circuit being efiective to cause the breakdown ofthe other of the tubes and the operation of the other of the relays.

4. In combination, a circuit, means for opening and closing saidcircuit, two three-element gasfilled tubes, two relays, the winding ofone of said relays being connected to an element of one of the tubes andthe winding of the other of said relaysbeing connected to an element ofthe other of said tubes, and circuit means for inductively connectingsaid signaling circuit to the control element of each of said tubes, theclosing of said circuit being effective to cause the breakdown of one ofthe tubes and operation of one of the relays, and the opening of saidcircuit being efiective to cause the breakdown of the other of the tubesand the operation of the other of the relays.

5. In combination, a circuit, means for opening and closing saidcircuit, two three-element gas-filled tubes, two relays, the winding ofone of said relays being permanently connected to an element of one ofthe tubes and the winding of the other of said relays being permanentlyconnected to an element of the other of said tubes, and circuit meansfor operatively associating said signaling circuit with the controlelement of each of said tubes, the closing of said circuit beingeffective to cause the breakdown of one of the tubes and operation ofone of the relays, and the opening of said circuit being efiective tocause the breakdown of the other of the tubes and the operation of theother of the relays.

6. In combination, a circuit, means for opening and closing saidcircuit, two three-element gasfilled tubes, two relays, the winding ofone of said relays being connected to an element of one of the tubes andthe winding of the other of said relays being connected to an element ofthe other of said tubes, circuit means for operatively associating saidsignaling circuit with the control element of each of said tubes, theclosing of said circuit being effective to cause the breakdown of one ofthe tubes and operation of one of the relays, and the opening of saidcircuit being efiective to cause the breakdown of the other of the tubesand the operation of the other of the relays, contacts on each of saidrelays for controlling the other of the relays, and other circuitcontrolling contacts on one of said relays.

7. In combination, a circuit, means for opening and closing saidcircuit, two three-element gas-filled tubes, two relays, the winding ofone of said relays being connected to an element of one of the tubes andthe winding of the other of said relays being connected to an element ofthe other of said tubes, circuit means for operatively associating saidsignaling circuit with the control element of each of said tubes, theclosing of said circuit being effective to cause the breakdown of one ofthe tubes and operation of one of the relays, and the opening of saidcircuit being eifective to cause the breakdown of the other of the tubesand the operation of the other of the relays, and means for holding saidone of the relays operated and for causing the deenergization of saidone of the tubes.

8. In combination, an impulse circuit, two three-element gas-filledtubes, circuit means for operatively associating said tubes with saidcircuit, a relay for operation in response to the ionization of one ofsaid tubes, a relay for operation in response to the ionization of theother of said tubes, and means for alternately connecting each of saidrelays to its associated tube for operation in response to impulses insaid circuit.

9. In combination, an impulse circuit, two three-element gas-filledtubes, circuit means for operatively associating said tubes with saidcircuit, a relay for operation in response to the ionization of one ofsaid tubes, a relay for operation in response to the ionization of theother of said tubes, and means for-alternately connecting each of saidrelays to its associated tube for operation in response to impulses insaid circuit, the cathode-anode circuit of each of the tubes being underthe control of the relay associated with the other of the tubes.

THOMAS L, DIMOND.

